Light Exposure to Treat Sleep Disruption in Older People

Disrupted Sleep in the Elderly: Light Exposure Studies


Lead Sponsor: National Institute on Aging (NIA)

Source National Institute on Aging (NIA)
Brief Summary

The purpose of this study is to test whether shifts in the timing of the biological clock to a later hour (phase delay shifts of the human circadian system) can be produced in response to four successive evenings of light exposure, and whether that phase shift will result in greater evening alertness and greater nighttime sleep efficiency. Three different light sources will be compared: 1) standard fluorescent light; 2) blue-enriched light; 3) incandescent fluorescent light.

Detailed Description

The endogenous circadian pacemaker (the natural biological rhythm of a 24-hour cycle) is a major determinant of the timing of sleep and sleep structure in humans. There are considerable data from animals and humans suggesting that the properties of the circadian pacemaker change with advancing age. It has been hypothesized that these changes may underlie the sleep disruption and reduction in daytime alertness observed in the elderly. Recent studies have confirmed the impact of endogenous circadian phase on REM sleep (Rapid Eye Movement--the period of sleep associated with dreaming) and have revealed that high sleep efficiency can only be maintained when there is a unique phase-relationship between the sleep episode and endogenous circadian phase. This phase-relationship is such that even a small change in the relative timing of the circadian pacemaker and the daily sleep episode can have a large impact on an individual's ability to consolidate sleep throughout the night, especially in older individuals.

In this field-laboratory study, participants will first be monitored for 3 weeks while living at home on a self-selected sleep-wake schedule. They will then enter the laboratory for a 13-day study. The laboratory study begins with 3 baseline days living on their habitual schedule, and participants will be allowed to leave the hospital each day, returning in the evening. After this 3-day baseline, the initial circadian phase will be estimated in a constant posture (CP protocol). This is followed by a 4-day light treatment, when the participant will be exposed to approximately a 2 hour light session each evening. As in the baseline, the participant will be allowed to leave the hospital during the daytime hours, returning in the early evening. Following the 4-day treatment, a second CP will be conducted. After the CP, a 3-day laboratory follow up will take place (similar to the baseline), and this will be followed by an ambulatory follow-up, where the participant will be monitored with an actigraphy monitor for 3 weeks while living at home (as in the ambulatory baseline). Sleep will be polysomnographically recorded (oxygen saturation, electrocardiography, air flow, respiratory effort, limb movement, eye and jaw muscle movement, and brain electrical activity) each night in the laboratory, blood samples will be collected during each CP so that the phase of the circadian rhythm of melatonin secretion can be assessed, and activity monitoring will continue from the ambulatory baseline through the ambulatory follow-up. Tests of performance and alertness will be conducted during the times the participant is awake in the laboratory.

Overall Status Suspended
Start Date June 2006
Completion Date September 2007
Primary Completion Date September 2007
Phase N/A
Study Type Interventional
Primary Outcome
Measure Time Frame
change in sleep efficiency
shift of circadian phase of melatonin secretion
Secondary Outcome
Measure Time Frame
change in alertness and performance
Enrollment 60

Intervention Type: Procedure

Intervention Name: light exposure



Inclusion Criteria:

- Sleep complaint

Exclusion Criteria:

- Sleep apnea

- Depression

- Periodic limb movements of sleep

- Restless Legs Syndrome

- History of stroke

- History of heart attack

- Uncontrolled medical condition

Gender: All

Minimum Age: 55 Years

Maximum Age: 80 Years

Healthy Volunteers: Accepts Healthy Volunteers

Overall Official
Last Name Role Affiliation
Jeanne F Duffy, PhD Principal Investigator Brigham and Women's Hospital
Facility: Brigham & Women's Hospital
Location Countries

United States

Verification Date

September 2007

Has Expanded Access No
Condition Browse
Study Design Info

Allocation: Randomized

Intervention Model: Parallel Assignment

Primary Purpose: Treatment

Masking: None (Open Label)